The Analytical Biology and Chemistry (ABC) Core Laboratory is a biological and chemical analysis arm of the Center for Environmental Health Sciences. It is a central resource in analytical biology and chemistry for CEHS research participants. In the laboratories of this facility core, combustion engineers, genetic toxicologists, analytical chemists, civil engineers, and investigators in other disciplines work together to test the linking hypothesis and to solve important problems affecting human health. The linking hypothesis is that a significant fraction of the point mutations and genetic changes in a human body are caused by exposure to environmental chemicals and radiation. In other words, they seek to test whether human diseases of unknown prominence, such as cancer and inherited diseases, are caused directly or indirectly by human exposure to environmental chemicals and radiation. For all CEHS projects that utilize the ABC/core resources, personnel meet regularly with project leaders and their students to ensure that a given task or project is completed with maximum scientific gain. The ABC/core therefore assists investigators and their students in all phases of their research projects, including: (1) experimental design, (2) sample acquisition, (3) sample preparation, (4) biological or chemical analysis, and (5) data interpretation. The close interaction of the ABC/core encouraged among investigators nurtures cross disciplinary collaboration. The ABC/core thus serves as an important incubator for concepts, models, projects and programs which could not otherwise come into fruition. In the chemical analysis laboratory complex, mixtures are fractionated and characterized. The fractions and components are processed here and then tested for mutagenicity in the biological assays lab.